Electromagnetic device.



No. 788,762. PATENTED MAY 2, 1905.

A. FAVARGER.

ELECTROMAGNETIC DEVICE.

APPLICATION FILED NOV. 25, 1902.

UNITED STATES Patented May 2, 1905.

PATENT OEEIcE.

ELECTROMAGNETIC DEVICE.

SPECIFICATION forming part of Letters Patent No. 788,762, dated May 2,1905.

Application filed November 25, 1902 Serial No. 132,818.

To all whom it 77mg concern:

Be it known that 1, ALBERT FAVARGER, a citizen of the Republic ofSwitzerland, and a resident of Neuohatel, Switzerland, have inventedcertain new and useful Improvements in Electromagnetic Devices, of whichthe following is a specification.

Most of theelectromagnets used in the numerous receiving instruments(such as electric clocks, speed-indicators, frequency-indicators, &c.,and in general all the apparatus for indicating or recording at adistance the variations of any phenomenon) which must transformintomotion an electric current have oscillatory armatures. If theoscillatory movements have in their turn to be transformed into angularmovements, rotating always in the same direction, as is the case if theyare embodied in secondary electric clocks or any other electricindicators, then it becomes necessary to have recourse to intermediatemechanical elements-such as impulsion-pawls, anchor-shanks, anchors,fiat springs, &c.- working on the periphery of a toothed wheel, which isusually called the escapementwheel and the axis of which carries thehand, the index, or the tracer. This mechanical transformer of anoscillatory movement into a rotary movement constitutes in its entiretyan arrangement which is relatively complicated and expensive and whichabsorbs, among others, on account of its friction an appreciable part ofthe disposable energy.

In the apparatus which constitutes the object of the present applicationsaid intermediate parts have been omitted, and the armature as well asthe two poles of the electromagnet are arranged in such a manner thatthis armature, being submitted to the direct influence of the polarattractions and repulsions, is made to describe angular intermittentmovement, the more or less rapid succession of which causes its axis toturn always in the same direction. This direction can be either that inwhich the hands of the clock move or the opposite one, as may bedesired. The accompanying drawing represents the invention in elevation.

1n the drawing, E is an electromagnet having the form of a horseshoe,the two poles p and p of which havetheir ends formed with pole-pieces,each of which is provided with a point and with an inclined flat orcurved side. Between the points of the two pole-pieces and p a disk 0.of soft iron, can turn without touching the pole-pieces. Said disk iskeyed on axis 0 and provided all over its circumference with teethhaving each one a point and an inclined portion which forms one of thelonger sides.

The relating positions of pole-pieces 7) and p and those of the teeth ofthe armaturedisk must be such that if the point of one of the polescoincides exactly with the point of the tooth next to it then the pointof the other poleis placed precisely in the middle of the intervalseparating the points of the two teeth which are next adjacent. Underthese conditions the two rays, 01: and cw, proceeding from axis 0 andpassing through the two points of the pole-pieces, meet each other at anangle comprising any whole number of teeth plus one half-tooth.

The permanent magnet A, on the one hand, influences by one of its endsthe two legs of the electric magnet and the pole-pieces and p, (to whichit communicates the corresponding polarity.) On the oth er hand, by itsother end it influences the toothed disk, and especially the teeth ofsaid disk which are in the nearest proximity with the pole-pieces 7) andp and to which teeth it communicates the corresponding polarity invertedas regards that of pole pieces. This being granted, let us admit thatthe points of the left polc and of tooth 1 next to it are opposite oneanother, or, to express it otherwise, let us admit that they coincide.Then the point of the right pole will be by one half-tooth in advance ofthe point of tooth 1. Let us also admit that the pern'ianent magnet Acommunicates south polarity to armature a and north polarity to the coreof electromagnet E.

As no current circulates in the wire of the bobbins of the electromagnetE, the position of the armature described heretofore and represented inthe figure will be assured, owing to the permanent magnet A, through thereciprocal vigorous attraction exercised among each other by the pointsof the pole-piece p (north) and of tooth 1., (south,) which are in close1n'oxin'1ity. It is true that, on theother hand, pole-piece 7), thepoint of which is at an equal distance from the points of the two teeth0 and 1, will exercise on the long side of tooth 1 an attraction whichwill tend to cause the turning of armature a in the direction of thearrow. However, this attraction is counteracted by the strongerattraction which exists between pole-piece 7) and that of tooth l andwhich continues as long as pole 7) remains a north pole. If now theposition of the armature being that shown in the figure, current ispassed from the alternator B into the bobbins of the electromagnet, sothat 7) becomes a south pole and p a north pole. Then there will becaused, on one hand, attraction between the north pole p on the rightside and tooth 1, (owing to the reciprocal action of the two sides andof the two points,) and, on the other hand, there will be brought aboutrepulsion between the point of south pole 7) on the left side and thepoint of tooth 1. These two forces will aid in causing armature a toturn in the direction of the arrow for the distance of exactly onehalf-tooth. In fact, as

soon as this angular movement has been ac-' complished the tangentialcomponents of the couple of magnetic forces cease, while the radiacomponents insure the immobility of the armature in its new position aslong as the current continues to pass in the same direction.

In order to pass a new current having a contrary direction to the formerone, pole p, to the right, which has become a south pole, will repulsetooth l, and pole p, to the left, which has become a north pole, willattract tooth 2, and so forth for the other alternate emissions.

Each time that an alternating current is passed the armature a will thuseffect a rotary angular movement of one half-tooth. If the armature hasthirty teeth, it will make a complete revolution during sixty passagesof alternating currents. If it has sixty teeth, it will describe arevolution during one hundred and twenty passages. make a revolutionduring ten passages, and so forth. This shows that the number of teethof the armature can always be selected, so that the index or the hand(for seconds or for minutes) may be secured right on the axis of thisarmature and that in this manner any intermediate gearing may beomitted, if this should be considered advantageous.

1f the passages of alternating current succeed each other with a certainrapidity, the

toothed armature assumes an intermittent rotary movement the angularspeed of which is exactly proportionate to that with which the currentsare produced. By this simple means it is possible to render at adistance two synchronous different or uniform movements of any kind, oneof which (the transmitter) produces the alternating currents, while theother (the receiver) is the nmvemento'l. the above-described apparatus.Moreover, the direction in which the armature 11. rotates may beselected at will, as it depends only on that direction given to theinclined sides of the teeth and of the pole-pieces.

Having thus described my invention, what 1 claim is An electromagnctmechanism for prod ueing a rotary movement by means of alternatingcurrents, comprising a polarized armature in the form of a tootheddissymnictrical wheel and an electromagnet provided with polepieceshaving positions which differ among themselves by one-half division oftooth with regard to the set of teeth of the wheel, whereby under theeffect of the alternating current the pole-pieces may cause the wheel toturn always in the same direction, by inter-missions of one-halfdivision of tooth after the magnetic alternating attractions andrepnlsions.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

ALBERT FAVAltUlCli. \Vitnesses:

Johns Cnarur, ARMANI) l lflltl-LIGLIG'I.

If it has five teeth, it will,

